Clock is a tanky roaming initiator that's very disrupting to the opposing team. His laning phase is strong in that he can't get bullied out of lane by anyone, and can always survivably resort to dragging creeps get his farm under his own tower. He can be aggressive with the right partner or passive and have a good game either way. Clock can play many roles, from support to offlane or mid. Aghs Scepter is incredible and should be rushed. Other than that, land your hooks and you should be fine.

There is the classic tankiness build with Aghs, Blade Mail and Eternal Shroud, or a more modern right click build that takes advantage of the Scepter attack speed in cogs that has you buy DMG items like Daedalus and Basher, Moonshard etc. Clock is extremely versatile in what he can built so have fun and adapt to each game well.